1 /*
   2  * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package com.sun.jndi.toolkit.dir;
  26 
  27 import javax.naming.*;
  28 import javax.naming.directory.SearchControls;
  29 import java.util.*;
  30 
  31 /**
  32   * A class for recursively enumerating the contents of a Context;
  33   *
  34   * @author Jon Ruiz
  35   */
  36 public class ContextEnumerator implements NamingEnumeration<Binding> {
  37 
  38     private static boolean debug = false;
  39     private NamingEnumeration<Binding> children = null;
  40     private Binding currentChild = null;
  41     private boolean currentReturned = false;
  42     private Context root;
  43     private ContextEnumerator currentChildEnum = null;
  44     private boolean currentChildExpanded = false;
  45     private boolean rootProcessed = false;
  46     private int scope = SearchControls.SUBTREE_SCOPE;
  47     private String contextName = "";
  48 
  49     public ContextEnumerator(Context context) throws NamingException {
  50         this(context, SearchControls.SUBTREE_SCOPE);
  51     }
  52 
  53     public ContextEnumerator(Context context, int scope)
  54         throws NamingException {
  55             // return this object except when searching single-level
  56         this(context, scope, "", scope != SearchControls.ONELEVEL_SCOPE);
  57    }
  58 
  59     protected ContextEnumerator(Context context, int scope, String contextName,
  60                              boolean returnSelf)
  61         throws NamingException {
  62         if(context == null) {
  63             throw new IllegalArgumentException("null context passed");
  64         }
  65 
  66         root = context;
  67 
  68         // No need to list children if we're only searching object
  69         if (scope != SearchControls.OBJECT_SCOPE) {
  70             children = getImmediateChildren(context);
  71         }
  72         this.scope = scope;
  73         this.contextName = contextName;
  74         // pretend root is processed, if we're not supposed to return ourself
  75         rootProcessed = !returnSelf;
  76         prepNextChild();
  77     }
  78 
  79     // Subclass should override if it wants to avoid calling obj factory
  80     protected NamingEnumeration<Binding> getImmediateChildren(Context ctx)
  81         throws NamingException {
  82             return ctx.listBindings("");
  83     }
  84 
  85     // Subclass should override so that instance is of same type as subclass
  86     protected ContextEnumerator newEnumerator(Context ctx, int scope,
  87         String contextName, boolean returnSelf) throws NamingException {
  88             return new ContextEnumerator(ctx, scope, contextName, returnSelf);
  89     }
  90 
  91     public boolean hasMore() throws NamingException {
  92         return !rootProcessed ||
  93             (scope != SearchControls.OBJECT_SCOPE && hasMoreDescendants());
  94     }
  95 
  96     public boolean hasMoreElements() {
  97         try {
  98             return hasMore();
  99         } catch (NamingException e) {
 100             return false;
 101         }
 102     }
 103 
 104     public Binding nextElement() {
 105         try {
 106             return next();
 107         } catch (NamingException e) {
 108             throw new NoSuchElementException(e.toString());
 109         }
 110     }
 111 
 112     public Binding next() throws NamingException {
 113         if (!rootProcessed) {
 114             rootProcessed = true;
 115             return new Binding("", root.getClass().getName(),
 116                                root, true);
 117         }
 118 
 119         if (scope != SearchControls.OBJECT_SCOPE && hasMoreDescendants()) {
 120             return getNextDescendant();
 121         }
 122 
 123         throw new NoSuchElementException();
 124     }
 125 
 126     public void close() throws NamingException {
 127         root = null;
 128     }
 129 
 130     private boolean hasMoreChildren() throws NamingException {
 131         return children != null && children.hasMore();
 132     }
 133 
 134     private Binding getNextChild() throws NamingException {
 135         Binding oldBinding = children.next();
 136         Binding newBinding = null;
 137 
 138         // if the name is relative, we need to add it to the name of this
 139         // context to keep it relative w.r.t. the root context we are
 140         // enumerating
 141         if(oldBinding.isRelative() && !contextName.equals("")) {
 142             NameParser parser = root.getNameParser("");
 143             Name newName = parser.parse(contextName);
 144             newName.add(oldBinding.getName());
 145             if(debug) {
 146                 System.out.println("ContextEnumerator: adding " + newName);
 147             }
 148             newBinding = new Binding(newName.toString(),
 149                                      oldBinding.getClassName(),
 150                                      oldBinding.getObject(),
 151                                      oldBinding.isRelative());
 152         } else {
 153             if(debug) {
 154                 System.out.println("ContextEnumerator: using old binding");
 155             }
 156             newBinding = oldBinding;
 157         }
 158 
 159         return newBinding;
 160     }
 161 
 162     private boolean hasMoreDescendants() throws NamingException {
 163         // if the current child is expanded, see if it has more elements
 164         if (!currentReturned) {
 165             if(debug) {System.out.println("hasMoreDescendants returning " +
 166                                           (currentChild != null) ); }
 167             return currentChild != null;
 168         } else if (currentChildExpanded && currentChildEnum.hasMore()) {
 169 
 170             if(debug) {System.out.println("hasMoreDescendants returning " +
 171                 "true");}
 172 
 173             return true;
 174         } else {
 175             if(debug) {System.out.println("hasMoreDescendants returning " +
 176                 "hasMoreChildren");}
 177             return hasMoreChildren();
 178         }
 179     }
 180 
 181     private Binding getNextDescendant() throws NamingException {
 182 
 183         if (!currentReturned) {
 184             // returning parent
 185             if(debug) {System.out.println("getNextDescedant: simple case");}
 186 
 187             currentReturned = true;
 188             return currentChild;
 189 
 190         } else if (currentChildExpanded && currentChildEnum.hasMore()) {
 191 
 192             if(debug) {System.out.println("getNextDescedant: expanded case");}
 193 
 194             // if the current child is expanded, use it's enumerator
 195             return currentChildEnum.next();
 196 
 197         } else {
 198 
 199             // Ready to go onto next child
 200             if(debug) {System.out.println("getNextDescedant: next case");}
 201 
 202             prepNextChild();
 203             return getNextDescendant();
 204         }
 205     }
 206 
 207     private void prepNextChild() throws NamingException {
 208         if(hasMoreChildren()) {
 209             try {
 210                 currentChild = getNextChild();
 211                 currentReturned = false;
 212             } catch (NamingException e){
 213                 if (debug) System.out.println(e);
 214                 if (debug) e.printStackTrace();
 215             }
 216         } else {
 217             currentChild = null;
 218             return;
 219         }
 220 
 221         if(scope == SearchControls.SUBTREE_SCOPE &&
 222            currentChild.getObject() instanceof Context) {
 223             currentChildEnum = newEnumerator(
 224                                           (Context)(currentChild.getObject()),
 225                                           scope, currentChild.getName(),
 226                                           false);
 227             currentChildExpanded = true;
 228             if(debug) {System.out.println("prepNextChild: expanded");}
 229         } else {
 230             currentChildExpanded = false;
 231             currentChildEnum = null;
 232             if(debug) {System.out.println("prepNextChild: normal");}
 233         }
 234     }
 235 }